<article id="wikiArticle">
<div></div>
<p><strong><code>handler.ownKeys()</code></strong> 方法用于拦截 <a href="Reference/Global_Objects/Reflect/ownKeys" title="静态方法 Reflect.ownKeys() 返回一个由目标对象自身的属性键组成的数组。"><code>Reflect.ownKeys()</code></a>.</p>
<h2 id="语法">语法</h2>
<pre><code  class="language-javascript">var p = new Proxy(target, {
  ownKeys: function(target) {
  }
});
</code></pre>
<h3 id="参数">参数</h3>
<p>下面的参数被传递给<code>ownKeys。this</code>被绑定在<code>handler上。</code></p>
<dl>
<dt><code>target</code></dt>
<dd>目标对象.</dd>
</dl>
<h3 id="返回值">返回值</h3>
<p><code>ownKeys</code> 方法必须返回一个可枚举对象.</p>
<h2 id="描述">描述</h2>
<p><code><strong>handler.ownKeys()</strong></code> 方法用于拦截 <a href="Reference/Global_Objects/Reflect/ownKeys" title="静态方法 Reflect.ownKeys() 返回一个由目标对象自身的属性键组成的数组。"><code>Reflect.ownKeys()</code></a>.</p>
<h3 id="拦截">拦截</h3>
<p>该拦截器可以拦截以下操作::</p>
<ul>
<li><a href="Reference/Global_Objects/Object/getOwnPropertyNames" title="Object.getOwnPropertyNames()方法返回一个由指定对象的所有自身属性的属性名（包括不可枚举属性但不包括Symbol值作为名称的属性）组成的数组。"><code>Object.getOwnPropertyNames()</code></a></li>
<li><a href="Reference/Global_Objects/Object/getOwnPropertySymbols" title="Object.getOwnPropertySymbols() 方法返回一个给定对象自身的所有 Symbol 属性的数组。"><code>Object.getOwnPropertySymbols()</code></a></li>
<li><a href="Reference/Global_Objects/Object/keys" title="Object.keys() 方法会返回一个由一个给定对象的自身可枚举属性组成的数组，数组中属性名的排列顺序和使用 for...in 循环遍历该对象时返回的顺序一致 。"><code>Object.keys()</code></a></li>
<li><a href="Reference/Global_Objects/Reflect/ownKeys" title="静态方法 Reflect.ownKeys() 返回一个由目标对象自身的属性键组成的数组。"><code>Reflect.ownKeys()</code></a></li>
</ul>
<h3 id="约定">约定</h3>
<p>如果违反了下面的约定，proxy将抛出错误 <a href="Reference/Global_Objects/TypeError" title="TypeError（类型错误） 对象用来表示值的类型非预期类型时发生的错误。"><code>TypeError</code></a>:</p>
<ul>
<li><code>ownKeys</code> 的结果必须是一个数组.</li>
<li>数组的元素类型要么是一个 <a href="Reference/String" title="此页面仍未被本地化, 期待您的翻译!"><code>String</code></a> ，要么是一个 <a href="Reference/Global_Objects/Symbol" title='Symbol()函数会返回symbol类型的值，该类型具有静态属性和静态方法。它的静态属性会暴露几个内建的成员对象；它的静态方法会暴露全局的symbol注册，且类似于内建对象类，但作为构造函数来说它并不完整，因为它不支持语法："new Symbol()"。'><code>Symbol</code></a>.</li>
<li>结果列表必须包含目标对象的所有不可配置（non-configurable ）、自有（own）属性的key.</li>
<li>如果目标对象不可扩展，那么结果列表必须包含目标对象的所有自有（own）属性的key，不能有其它值.</li>
</ul>
<h2 id="示例">示例</h2>
<p>下面的代码拦截 <a href="Reference/Global_Objects/Object/getOwnPropertyNames" title="Object.getOwnPropertyNames()方法返回一个由指定对象的所有自身属性的属性名（包括不可枚举属性但不包括Symbol值作为名称的属性）组成的数组。"><code>Object.getOwnPropertyNames()</code></a>.</p>
<pre><code  class="language-javascript">var p = new Proxy({}, {
  ownKeys: function(target) {
    console.log('called');
    return ['a', 'b', 'c'];
  }
});

console.log(Object.getOwnPropertyNames(p)); // "called"
                                            // [ 'a', 'b', 'c' ]</code></pre>
<p>下面的代码违反了约定</p>
<pre><code class="language-js example-bad">var obj = {};
Object.defineProperty(obj, 'a', { 
  configurable: false, 
  enumerable: true, 
  value: 10 }
);

var p = new Proxy(obj, {
  ownKeys: function(target) {
    return [123, 12.5, true, false, undefined, null, {}, []];
  }
});

console.log(Object.getOwnPropertyNames(p)); 

// TypeError: proxy [[OwnPropertyKeys]] 必须返回一个数组 
// 数组元素类型只能是String或Symbol
</code></pre>
<h2 id="标准">标准</h2>
<table class="standard-table">
<tbody>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
<tr>
<td><a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">[[OwnPropertyKeys]]</small></a></td>
<td><span class="spec-Standard">Standard</span></td>
<td>Initial definition.</td>
</tr>
<tr>
<td><a class="external" href="https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">[[OwnPropertyKeys]]</small></a></td>
<td><span class="spec-Draft">Draft</span></td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容">浏览器兼容</h2>
<div><div class="blockIndicator warning"><strong><a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">We're converting our compatibility data into a machine-readable JSON format</a></strong>.
            This compatibility table still uses the old format,
            because we haven't yet converted the data it contains.
            <strong><a class="new" href="/zh-CN/docs/MDN/Contribute/Structures/Compatibility_tables" rel="nofollow">Find out how you can help!</a></strong></div>
<div class="htab">
<a id="AutoCompatibilityTable" name="AutoCompatibilityTable"></a>
<ul>
<li class="selected"><a>Desktop</a></li>
<li><a>Mobile</a></li>
</ul>
</div></div>
<div id="compat-desktop">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Chrome</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari</th>
</tr>
<tr>
<td>Basic support</td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td><a href="/en-US/Firefox/Releases/18" title="Released on 2013-01-08.">18</a> (18)</td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
</tr>
</tbody>
</table>
</div>
<div id="compat-mobile">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Chrome for Android</th>
<th>Firefox Mobile (Gecko)</th>
<th>IE Mobile</th>
<th>Opera Mobile</th>
<th>Safari Mobile</th>
</tr>
<tr>
<td>Basic support</td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td>18.0 (18)</td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
</tr>
</tbody>
</table>
</div>
<h2 id="兼容性注意事项">兼容性注意事项</h2>
<h3 id="Firefox火狐">Firefox火狐</h3>
<ul>
<li>在Gecko 42 (Firefox 42 / Thunderbird 42 / SeaMonkey 2.39)版本中, <code>ownKey</code> 的实施已经更新了，为了反映最终的ES5标准 (see <a class="external" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1049662" rel="noopener" title='FIXED: Update ES6 scripted proxies "ownKeys" to ES6 final'>bug 1049662</a>):

  <ul>
<li>现在需要检查结果是不是数组以及数组元素类型是不是string或symbol.</li>
<li>枚举重复的自有的属性名称不再失败.</li>
</ul>
</li>
</ul>
<h2 id="另见">另见</h2>
<ul>
<li><a href="Reference/Global_Objects/Proxy" title="Proxy 对象用于定义基本操作的自定义行为（如属性查找，赋值，枚举，函数调用等）。"><code>Proxy</code></a></li>
<li><a href="Reference/Global_Objects/Proxy/handler" title="处理器对象用来自定义代理对象的各种可代理操作。"><code>handler</code></a></li>
<li><a href="Reference/Global_Objects/Object/getOwnPropertyNames" title="Object.getOwnPropertyNames()方法返回一个由指定对象的所有自身属性的属性名（包括不可枚举属性但不包括Symbol值作为名称的属性）组成的数组。"><code>Object.getOwnPropertyNames()</code></a></li>
<li><a href="Reference/Global_Objects/Reflect/ownKeys" title="静态方法 Reflect.ownKeys() 返回一个由目标对象自身的属性键组成的数组。"><code>Reflect.ownKeys()</code></a></li>
</ul>
</article>